I'm trying to understand how to handle db connections in a multi-theaded windows program.It I have this simple class:
public class MyClass
private myConn as new sqlconnection
private MyThreadPool(5) as Thread
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Im writing a small application that need to make up to 300 socket connections at the same time. However i'm pretty confused on how to approach this. My first theory is to have my main thread to manually fire up 300 new threads that each handle all that needs to be done. Another theory is to fire up lets say 10 threads that makes 30 async connections. My last theory is to have my mainthread work with all 300 async connections together with everything else. The question to this is what would be the most effective way to go to save resources and maintain speed.
View 1 RepliesI'm running a program where I call a function which creates a database connection and then runs a stored procedure. I call this function four times from four separate threads. I get an error (Login failed for user 'sa'. The user is not associated with a trusted SQL Server connection.
Exception Source:
.Net SqlClient Data Provider)
when I use multiple threads, but if I have the threads run one after another I have no
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Using VB.Net and SQL Server 2008 R2: I have recently had a database that using sp_who2 reflects a connection ".Net SqlClient Data Provider" is still active even though the .Net application has closed and disposed of all connections.
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I'm populating a listview with a list of databases on a selected SQL instance, then retrieving a value from each database (It's internal product version, column doesn't always exist) I'm calling the below function to populate the second column of the listview:
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I searched araound and having some difficulties in implementing one scenario with SQL Server 2000 and sybase.I have two SQL servers on different locations naming ServerA (MSSQL Server) and ServerB (Sybase server).I have a table called SALARY.Whenever I insert one record to customer SALARY in ServerA, I also will insert it into ServerB.If should any of them failed, both of them should be rolled back.I am using Asp .Net with VB for the programming.I do not have the right to change / add table in Server B. The only thing allowed in Server B is insert/delete/update record.I looked around and find a method to use TransactionScope but I am not quite sure it is the right way to do.url...
View 1 RepliesI am developing an Application that uses TCP To listen for connections, and then when a message is sent to the server and then it alerts the IP that is running the server. (Lets say the server is on a iPhone, and some how the iPhone gets a text message, which alerts a tcp server running in the background via a .jar, it would send the owner of the iPhone a message on the computer telling it it has a text. This is just an example though, but I think it gets the general idea across. I've been trying to do this, and I can connect to a TCP Server (using 127.0.0.1:8888 for testing purposes, will move to a solid IP and Port later). I can start the server (its still buggy and under development) but i don't know how to connect to the server via an application, and when a certain message is received to alert the IP Running the server.
My Server Code is:
Dim serverSocket As New TcpListener(8888)
Dim clientSocket As TcpClient
Dim infiniteCounter As Integer
Dim counter As Integer
serverSocket.Start()
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Now I know that to connect you'd do something like
Code:
Dim clientSocket As New System.Net.Sockets.TcpClient()
Dim serverStream As NetworkStream
clientSocket.Connect("127.0.0.1", 8888)
serverStream = clientSocket.GetStream()
And I know I would have to use some sort of Byte() method to send/receive messages, but I am at a loss on how to set it all up.
I need to download a bunch of pages from a web server, ie. spidering. I know that servers are typically configured to only allow a couple of concurrent connections from a given IP, but that would already halve the total time to run the script instead of downloading one page at a time.
View 4 Repliesi've been previously using Visual Studios built in wizards for manipulating data access to and from an MSAccess Database, however just recently i coded my own classes and connections to the database, ive been able to select, update and delete records effectively however my problem comes with inserting records.
I have a 3 tiered table database:Tbl_PO, Tbl_Parts, Tbl_Shipments each po has multiple parts, each part has multiple shipments.when i insert a record into the tbl_PO, i need to retrieve the ID used on that insertion.
I am using two SQL connections in my Program. I declare them like this:
Public SQLcon As New SqlConnection("server=(local);database=master;Trusted_Connection=True;")
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How do I go about closing a connection if I redirect before I can close it? Does it close when the new page loads? For example:
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This thread (Question) is a continuation of a question answered by JohnWein. the original question asked by me in this thread:http://social.msdn.microsoft.com/Forums/en-US/vbgeneral/thread/4d9b44a0-91ed-4f64-a3a2-74afffce2256 an this is the answer:
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The question is, in the case of four connections, how can I make sure that all points are connected with minimum number of connections using the same above code?
I have a Visual Studio 2008-SQL Server 2005 app that will be throwing alot at it. It's my testbed learning app. I'm also a student of this craft(43 years young) like another poster posted on another thread. I come from a PICK/BASIC jBase background. Anyway as-is my app has a connection to the database that is opened on form load. I close the connection on form close. It's a one form app currently. Is this wrong? It seems that maybe I should not have a connection opened possibly all day. I'm looking into incorporating Datasets, dataAdapters into my next phase of evolution. I looked at the material and it's tough. For me anyway. But I will get into it. I will fetch the data into a dataset so that I can keep the connection open only for a little while. I was turned on to this "keep the connection just as long as you need it" idea from someth
View 3 RepliesI am making a web browser and I was wondering how I could create connections through proxies. Right now the browser only uses UDP packets, so any info specifically on that would be great.
View 8 RepliesThe current project that I'm working on is mainly employing a database back-end, and I have a few questions regarding database connections in .Net, before I actually convert.
For VB6, I connect to my databases using ADODB connections and recordsets in code only, and not by binding controls. I perform my queries using SQL statements..For differentations in the type of database, such as connecting to a MySql, a MsSql, or an access database, it was mainly the connection string that had to be changed.. and ofcourse installing the drivers.
Now for VB.Net, I believe this can be done using the System.Data assembly. While looking into it, I've seen that it has a lot of members, such as System.Data.Odbc, System.Data.OleDb, System.Data.SqlClient.
My question is, what is the main difference between those namespaces (just briefly)? I would like to generally understand the main differences before I start with anything. I have also heard about LINQ. It looked very alien to me in the MSDN library. (PS: what's the deal with Ado.Net?)
i'm using Visual Basic 2008 - Office 2007 - addin for ppt.
ok i'm going to delete the other thread. i'm going to rephrase and try to explain as clearly as possible.
I need to find a code that (when i click the "Search" Button) will start searching for all available lan and wireless connections.
All the available selections will be shown in a List Box provided.
Once i find one i want to use, i can stop the search (by pressing another button "Stop" in this case) or just straight away click the one i want and press another button ("Select" in this case) and if it needs a password or WEP then it will display or it will just connect without asking.
Im making a small servermanager for a game. I have a list of players with their IP's that are currently connected to the the whole game. I want to find out what IP's are connected to a certain process so I can match these with the list of players and then add the players that are in the server hosted by this servermanager, into the playerlist.Adding players to that list and looking them up for a matching IP already works. I just cant figure out how to find all the IP's that are connected to a certain process.
View 1 RepliesI'm using a TcpListener and TcpClient to search for a connection on a certain port,and display a message when a connection is made, but i do not know how to do this. My code so far:
Dim port As Integer = 81
Dim serverSocket As New TcpListener(port)
Dim clientSocket As TcpClient
Dim c As Integer
Dim ic As Integer
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I wrote application which displays tcp connections to the PC, but how can i terminate them? [code]...
View 2 RepliesOK here is some code I nicked from web and I have changed some things, it works but only accepting one client, how do I make this accept multiple clients?
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I searched on google for these terms : "How to see all open connections in vb.net" and it should be for a server im running and it would be like to see witch users are connected (ip) and then if i type in the console -disconnect ip then the user will be disconnected from the server but is this technical posibble ?
View 4 RepliesI am currently working on an asp.net web page with a GridView displaying a table from a database.This GridView has 4 DropDownLists that will be used to filter the data shown on the GridView. When the page loads 4 Sub routines are run, each one connecting to the database with a select statement to fill the DropDownList with relevant filter headings.
Initially, I had one connection with a loop that populated all of the drop downs but these contained duplicates. I then split the filling of each DDL so that the select statements could contain DISTINCT. I would like (and am sure there is a way here) to be able to populate all of the DDLs with data from one connection.
Code for one connection:
Protected Sub FillDepDDL()
Dim conn As New SqlConnection()
conn.ConnectionString =
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The other 3 column names: FirstName > DDLFN, LastName > DDLLN, Wage > DDLWag.This is only a test DB and the princibles learned here will be applied to a larger live project.
I was wondering, if there is a way to block incoming connections from specific ip adress that tries to connect to computer
I assume that it cant be via windows host files
I need to change the connection string of all tableadapters at runtime, can anyone tell me for the best way to do it?I have a conection string in my settings, that i can't change at runtime (application scope), i could go to dataset.designer and change the value to a new variable but i don't think this is a good method.
View 3 RepliesI'm pretty new to VB.NET and connecting to SQL Server.What is considered best practice when building an app that needs to connect frequently to a SQL Server DB to fetch, write, delete and update records?Should a connection be opened at app startup (a connection at start is opened to validate the user) and left open for subsequent transactions or should a connection be opened, closed and disposed of each time a read/write to the DB is required?
View 3 RepliesI'm using an xsd file for a couple of my data sets that I'm using to read access databases. While this is great, I just got a new requirement that allows the user to change the link to the access database on their computer. Is there any way to allow them to set the path while still being able to use the xsd files, instead of doing it all through code?
View 2 RepliesI am new(ish) to Visual Basic and i have learned from looking at old VB6 code for programs that have been made for us in the past, this includes using the old ADODB connections and FlexGrids which both have been changed in VB.Net to OLEDB and DataGridView.I have started to understand the way the connections and datasets etc are created but i am struggling to get to where i was with the old code (I am trying to completely upgrade the code from FlexGrid).This is the VB6 Code i am trying to upgrade from:
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I have a .net Application that writes text to a serial COM port, a POS reciept printer to be more exact. i am using the Rs232 class library to write and read to a serial device.My problem is now with some clients that have updated their operatingsystem to WIN7 64bit version, have trouble to create a connection to the COM-port. the com-port seemes to get occupied with some other process and that blocks my application to opening a new connection. so for my question, does anyone know how i can close all connections to a com port? or see whats blocking it? once again this seems to only to affect win7 and 64bit users.
View 1 Replieswhat libraries can i use to make http connections in visual basic? like cURL library for VB ?i am looking for something like cURL for visual basic.
View 1 RepliesI'm working on a vb.net application connecting to mysql db which will have alot of users using it.
How should I deal with the user registration?I mean, I used to create a table with a username and password fields to store the users data in it, but in this case all the users will connect to the database with the same username and password of the server (in the connection string)
I need a pointer on how to do this thing right.What would happen if many connections established from many computers with the same user and password in the connection string?